The thing about a game within a game is that time flows differently at the different levels. The time taken to play out a given situation
can take twenty times the amount of time depicted. A combat that takes 3 minutes of game time can easily take an hour to play out.
In the next level up, that hour of gaming will take 20 hours to play. And three levels up, you're looking at over two weeks of roleplaying,
to simulate just 3 minutes of combat.

We've all played games like this.

In the real world of the Heists & Hypnagogic Hallucinations universe, of course, Inception doesn't exist.
That's the premise of this entire comic, after all. But most of the other things we know and love (such as perpetual motion tops)
do, albeit modified by the lack of Inception:

Leonardo DiCaprio is known (barely) for doing voiceovers for poorly selling computer games, but gains widespread fame
after his appearance in the first Futurama movie.

Michael Caine is known primarily for his role in Jaws: The Revenge.

Nerdy guys make YouTube videos of themselves figure skating instead of running around the walls and ceiling of hotel corridors.

Without the success of Inception to spark interest in intricate deceptions, Mission: Impossible was never revived
with a movie and a new series, and remains an obscure short-running TV show.

The Lawnmower Man was never made into a film. Stephen King fans never had it so good.

The major hi-tech noir background that pervades all of Western culture is Blade Runner, despite it never being much good.
The original film was remade recently into a new, updated television series with a bigger budget, high-tech computerised special effects, and edgy writing.
And it sucked.

Throughout the 2010s, all the greatest Hollywood blockbusters were big-budget ballet productions.

Transcript

Cobb: I know inception is possible. I did it to my wife, to make her realise we were in a roleplaying game.Cobb: If you die in the game, you get to roll up a new character.Cobb: But she became obsessed with the idea, and killed herself in reality.Ariadne: And you want us to go into a third level? A game within a game within a game? She still exists as an NPC down there, doesn't she?
{a mélange of panels showing various random images of tilting corridors, mazes, a crumbling coastline, Penrose stairs, a spinning top, people walking up a vertical street, a van falling off a bridge, and two youg children}
{the entire comic repeated at a smaller scale, within which the entire comic is repeated at a smaller scale, within which the entire comic is repeated at a smaller scale, within which the entire comic is repeated at a smaller scale, within which the entire comic is repeated at a smaller scale, within which the entire comic is repeated at a smaller scale, ...}Ariadne: What if she was right? What if our reality is a game?
{beat}
{Cobb looking straight at camera}Cobb: What do you think?